Spiraea plant named ‘MAD-SP2’

ABSTRACT

A new and distinct cultivar of  Spiraea  plant named ‘MAD-SP2’, characterized by its pure white colored flowers, medium green foliage and moderately vigorous, compact, low mounded growth habit. Also, for the last 5 years of its existence  Spiraea  ‘MAD-SP2’ has proven to be leaf spot resistant.

Botanical designation: Spiraea japonica.

Cultivar denomination: ‘MAD-SP2’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Spiraea,botanically know as Spiraea japonica, and hereinafter referred to by thecultivar name ‘MAD-SP2’.

The new Spiraea japonica ‘MAD-SP2’ is a product of a planned Spiraeavariety trial program conducted by the inventors at a horticulture farmin Athens, Ga. The objective of the Spiraea breeding strategy is tocreate new plant cultivars with abundant numbers of inflorescence,brighter and more vibrant flower colors, compact growth habit andpotential leaf spot resistance. These and other qualities are enumeratedherein.

The new Spiraea japonica ‘MAD-SP2’ is a product of open pollinationmethod on the mother plant, Spiraea japonica ‘Little Princess’ (patentstatus unknown) in Athens, Ga., and seed was collected in the fall of2014. The collected seed was planted in late 2014. In 2015, out ofseveral hundred seedlings that were produced, nine initial seedlingswere selected based on compact growth habit, flower color, foliagecolor, and resistance to leaf scorch and leaf spot. In 2020, two of the9 seedlings were deemed superior and were selected: the white floweringnew Spiraea ‘MAD-SP2’ and the pink flowering Spiraea ‘MAD-SP1’.

Asexual reproduction of the new Spiraea japonica ‘MAD-SP2’ usingsoftwood cuttings was first accomplished by the inventor in the summerof 2015 at a horticulture farm in Athens, Ga., and has been continued inAthens, Ga. (Zone 7b) since 2015. Observations of the resulting‘MAD-SP2’ progeny have shown that the unique features of this newSpiraea japonica ‘MAD-SP2’ are stable and reproduced true to type insuccessive generations.

SUMMARY OF THE INVENTION

The new Spiraea cultivar ‘MAD-SP2’ has not been observed under allpossible environmental conditions. The phenotype may vary somewhat withvariations in environment and cultural practices such as temperature,water and fertility levels, soil types, light intensity, and day lengthwithout, however, any variance in genotype.

The following traits have been repeatedly observed and are determined tobe the unique and distinguishing characteristics of the new Spiraeajaponica cultivar named ‘MAD-SP2’. In combination, these traits set‘MAD-SP2’ apart from all other existing varieties of Spiraea japonicaknown to the inventors.

-   -   1. Pure white colored flowers that are self-cleaning.    -   2. Medium green colored foliage.    -   3. Moderately vigorous, compact, low-mounding growth habit    -   4. Leaf spot resistance

Plants of the new cultivar differ from plants of the female parent,‘Little Princess’ Spiraea, primarily by having white flowers. Of themany commercially available Spiraea cultivars, the most similar incomparison is Spiraea japonica ‘albiflora’; however, in side by sidecomparisons, plants of the new cultivar differ from other whiteflowering varieties such as Spiraea ‘albiflora’. In 5 years ofobservation, ‘MAD-SP2’ has maintained a 3 ft.×3 ft. growth habit, while‘albiflora’ can get up to 6 ft. ‘MAD-SP2’ has been able to maintain itspure white flowers longer than other white flowering spiraeas, and, thusfar, it has shown superior leaf spot resistance.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographic illustrations show the overallappearance and distinct characteristics of the new cultivar of Spiraeajaponica ‘MAD-SP2’ showing the colors as true as possible. Colors in thephotographs may differ slightly from the color values cited in thedetailed botanical description, which accurately describes the colors ofthe new Spiraea japonica ‘MAD-SP2’. The photographs were taken of plantsgrown outdoors in Watkinsville, Ga. on May 21, 2021.

The photographs labeled FIGS. 1A and 1B depict close-up views of atypical 2-year-old ‘MAD-SP2’ plant in Spring showing the inflorescence,with small white flowers, as well as buds and the medium green foliage.

The photograph labeled FIG. 2 depicts a top-view of a typical 2-year old‘MAD-SP2’ plant showing the substantially compact, low-mounding, growthhabit, as well as the white flowers and medium green foliage.

The photograph labeled FIG. 3 also depicts a top-view of a typical2-year-old potted ‘MAD-SP2’ plant showing the compact, low-mounding,growth habit, as well as the white flowers and medium green foliage.

The photograph labeled FIG. 4 depicts on overhead view of a typicaltwo-year-old Spiraea ‘little princess’ plant for comparison, showing themuch pink flowers (compared to the pure white flowers of the ‘MAD-SP2’plants depicted in the other photographs).

DETAILED BOTANICAL DESCRIPTION

The following traits have been consistently observed in the originalplant of this new variety and in asexually propagated progeny grown fromAthens, Ga. (Zone 7(b)), and, to the best knowledge of the inventors,their combination forms the unique characteristics of the new variety‘MAD-SP2’.

Throughout this specification, color names beginning with a small lettersignify that the name of that color, as used in common speech, is aptlydescriptive. Color names beginning with a capital letter designatevalues based upon The R.H.S. Colour Chart, 5^(th) edition published byThe Royal Horticultural Society, London, England in 2015, except wheregeneral terms of ordinary dictionary significance are used.

The aforementioned photographs and following observations, measurements,and values describe plants of the Spiraea japonica cultivar named‘MAD-SP2’. Data were collected from a horticulture farm and nursery inAthens, Ga. from 2-year-old plants (from cuttings from stock plants andgrown in 3-gallon containers in a green house in Athens, Ga. The averagelow temperatures ranged from about 33-42° F. in the winter and theaverage high temperatures ranged from about 85-92° F. in summer.

-   Botanical classification: Spiraea japonica ‘MAD-SP2’.-   Commercial classification: Ornamental shrub.-   Parentage: Open pollination of female parent Spiraea japonica    ‘Little Princess’.-   Growth and propagation:    -   -   Propagation type.—Terminal cutting.        -   Growth rate.—About 10-14 days to initiate roots; about 21            days to produce rooted cutting; Commercial crop time — about            15 weeks from rooted cutting to finish in a 3-gallon            container.        -   Root description.—Fibrous and fine, white to brown in color.        -   Rooting habit.—Freely branched, dense.-   Plant description:    -   -   Form.—Compact, low-mounding growth habit.        -   Branching habit.—Freely branching.        -   Usage.—Various uses, such as container patio plants, potted            plants, border, hedge, and mass planting.        -   Vigor.—Moderately vigorous.        -   Size of plant.—A. Height (cm): from soil level to top of            plant, about 36 cm. B. Plant diameter and area of spread            (diameter of the canopy): about 40 cm.        -   Branch/stem.—A. Quantity: about 14-16 main stems per plant            with approximately 10-12 lateral branches per stem. B.            Length: About 20 cm. C. Base Diameter: About 3 mm. D.            Aspect: erect to about 45° from center. E: Odor (of bruised            stem): none. F. Internode length: central internode about            11 mm. G: Texture of mature stem: woody. H: Color (RHS): 1.            young stem: 145A. 2. mature stem: 200A. I: Strength of            lateral branches: strong.        -   Leaf.—A. Leaf type: simple. B. Mature size (L×W): About 4-5            cm×about 2-3 cm. C. Arrangement on stem: alternate. D.            Aspect: about 45°. E. Color (RHS): 1. young foliage: upper            surface — 143B, venation 151 A; lower surface — 142C,            venation 143D. 2. mature foliage: upper surface — 137B,            venation 151 A; lower surface — 136C, venation 151A. F. Leaf            Number: Average of about 40-50 per stem. G. Apex: acute. H.            Base: cuneate. I. Margin: serrate. J. Shape: ovate. K.            Pubescence: yes. L. Venation: pinnate. M. Texture of upper            surface: glabrous, moderately rugose. N. Texture of lower            surface: glabrous, ribbed. O. Odor when crushed: none            detected.        -   Petiole.—A. Length: About 3 mm. B. Color (RHS): upper and            lower surface, 151A. C. Texture: glabrous. D. Diameter:            About 1 mm. E. Sheath: unknown.        -   Inflorescence(s).—A. Type: compound corymbs. B. Number per            Plant: about 30-32. C. Size: height — about 2-3 cm; diameter            — about 8-10 cm. D. Color (RHS): at full bloom: NN155B. E.            Longevity: about 20 days. F. Aspect: facing upwards to            slightly outward. G. Peduncle. 1. Length: about 1 cm. 2.            Diameter: about 2 cm. 3. Color (RHS): 59C. 4. Texture:            glabrous. 5. Strength: strong. 6. Aspect: erect to about 45            degrees from branch to axis. 7. Shape: rounded.        -   Flower.—A. Number per Inflorescence: about 180-200. B. Type:            single/rotate not persistent. C. Shape: whorl. D. Size            (corolla): diameter — about 5 mm; depth — about 3 mm. E.            Aspect: upright. F. Symmetry: G. Color at peak bloom (RHS):            NN155B. H. Fragrance: none detected. I. Time of full            maturity: 10 days. J. Time range for showiness: flowers            emerge in May in zone 7b and persist until mid-October. K.            Bud (just before opening): 1. Diameter: about 2 mm. 2.            Shape: globose. 3. Color (RHS): NN155D. 4. Longevity:            currently unknown. L. Petals: 1. Number: 5. 2. Size (l×w):            about 3 mm×about 3 mm. 3. Shape: orbicular. 4. Apex:            rounded. 5. Base: obtuse. 6. Margin: entire. 7. Color when            fully opened (RHS): upper and lower surfaces — NN155B. 8.            Texture: upper and lower surface — glabrous. 9. Arrangement:            single whorl. M. Pedicels: 1. Color (RHS): 143B. 2.            Texture/Pubescence: glabrous. 3. Length: about 5 mm. 4.            Diameter: about 1 mm. 5. Aspect: erect. 6. Strength:            strong. N. Sepal(s): 1. Number: 5. 2. Size (l×w): about 3            mm×3 mm. 3. Shape: lanceolate. 4. Apex: acute. 5. Base:            fused. 6. Margin: entire. 7. Texture: upper and lower            surface — glabrous. 8. Arrangement: single whorl. 9. Color            at peak of bloom (RHS): a. Upper surface: 135C. b. Lower            surfaces: 137C. O. Calyx: 1. Shape: star shaped. 2.            Diameter: about 4 mm. 3. Depth: about 4 mm. P. Male            reproductive structures (Androecium): 1. Stamen. a. Number:            about 35-40 per flower. b. Length: about 5 mm. 2. Anther: a.            Length: less than about 1 mm. b. Shape: globose. c. Color            (RHS): 162B. d. Texture/pubescence: pubescent. 3.            Filament: a. Length: about 5 mm. b. Color (RHS): NN155D. 4.            Pollen: a. Quantity: slight. b. Pollen color (RHS): 162B. Q.            Female Reproductive structures (Gynoecium): 1. Pistil: a.            Length: about 2 mm. b. Color (RHS): N15D. c. Pubescence:            yes. 2. Stigma: a. Shape: garrated. b. Color (RHS): N15D. c.            Pubescence: yes. 3. Style: a. Length: about 2 mm. b. Number:            5 styles fused to 1 ovary. c. Color (RHS): NN155D. d.            Pubescence: unknown. 4. Ovary: a. Length: about 0.5 mm. b.            Color (RHS): N144C. c. Pubescence: yes.        -   Fruit.—None observed.        -   Seed.—None observed.-   Weather/temperature tolerance: Plants of the new Spiraea have been    observed to regularly tolerate temps as high as 38° C./100° F. in    the summer. Conversely it can regularly tolerate −30° F. in the    winter. USDA Zone range 4-9.-   Disease/pest resistance: To date, plants of the new Spiraea have    been observed to have the most leaf spot resistance of any Spiraea    cultivar observed.

It is claimed:
 1. A new and distinct cultivar of the Spiraea plant named‘MAD-SP2’ as illustrated and described herein.